PNNL

Abstract

CeO2 nanorod based catalysts for the base-free synthesis of azoxy-aromatics via transfer hydrogenation of nitroarenes with ethanol as hydrogen donor have been synthesized and investigated. The oxygen vacancies (Ov) and base sites are critical for their excellent catalytic properties. The Ov, i.e., undercoordinated Ce cations, serve as the sites to activate ethanol and nitroarenes by lowering the energy barrier to transfer hydrogen from a-Csp3-H in ethanol to the nitro group coupling it to the redox reactions between Ce3+ and Ce4+. At the same time, the base sites catalyze the condensation step to selectively produce azoxy-aromatics. The catalytic route opens a much improved way to use non-noble metal oxides without additives for the selective functional group reduction and coupling reactions. The authors thank the support of the Project was supported by the National Natural Science Foundation of China (21922513), and the Natural Science Foundation of Hubei Province (No. 2020CFA096). J. A. L. was supported by the U.S. Department of Energy (DOE), Office of Science, Office of Basic Energy Sciences (BES), Division of Chemical Sciences, Geosciences and Biosciences (Impact of catalytically active centers and their environment on rates and thermodynamic states along reaction paths, FWP 47319).